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Questions part 2: Evolution und Mechanismen der Entwicklung (VL vom
12.12.11)
Due: 11:59am on Wednesday, December 14, 2011
Note: You will receive no credit for late submissions. To learn more, read your instructor's Grading Policy
Chapter 25 Question 16
Description: [[Bloom's Taxonomy: Knowledge/Comprehension ]] (a) What is true of the Cambrian
explosion?
Part A
What is true of the Cambrian explosion?
ANSWER:
The Cambrian explosion marks the appearance of filter-feeding animals
in the fossil record.
Only the fossils of microorganisms are found in geological strata older
than the Cambrian explosion.
The Cambrian explosion is evidence for the instantaneous creation of
life on Earth.
Recent evidence supports the contention that the Cambrian explosion
may not have occurred over a longer period of time than was once
thought.
There are no fossils in geological strata that are older than the
Cambrian explosion.
Chapter 25 Question 63
Description: [[Bloom's Taxonomy: Synthesis/Evaluation ]] (a) The following question refers to the
description below. All animals with eyes or eyespots that have been studied so far share a gene in
common. When mutated, the gene -Pax causes lack of eyes in...
Part A
The following question refers to the description below.
All animals with eyes or eyespots that have been studied so far share a gene in common. When
mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and
other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so
few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye
formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common
ancestor more than 500 million years ago.
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Fruit fly eyes are of the compound type, which is structurally very different from the camera-type
eyes of mammals. Even the camera-type eyes of molluscs, such as octopi, are structurally quite
different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions
of Pax-6. The fact that the same gene helps produce very different types of eyes is most likely due
to
ANSWER:
differences in the control of Pax-6 expression among these organisms.
the independent evolution of this gene at many different times during
animal evolution.
the few differences in nucleotide sequence among the Pax-6 genes of
these organisms.
variations in the number of Pax-6 genes among these organisms.
Chapter 25 Question 64
Description: [[Bloom's Taxonomy: Synthesis/Evaluation ]] (a) The following question refers to the
description below. All animals with eyes or eyespots that have been studied so far share a gene in
common. When mutated, the gene -Pax causes lack of eyes in...
Part A
The following question refers to the description below.
All animals with eyes or eyespots that have been studied so far share a gene in common. When
mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and
other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so
few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye
formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common
ancestor more than 500 million years ago.
Pax-6 usually causes the production of a type of light-receptor pigment. In vertebrate eyes, though,
a different gene (the rh gene family) is responsible for the light-receptor pigments of the retina. The
rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene causes production
of c-opsin, which helps regulate the worm's biological clock. Which of these most likely accounts for
vertebrate vision?
ANSWER:
In animals more ancient than ragworms, the rh gene(s) coded for visual
receptor pigments; in lineages more recent than ragworms, rh has
flip-flopped several times between producing biological clock opsins
and visual receptor pigments.
During vertebrate evolution, the rh gene for biological clock opsin was
co-opted as a gene for visual receptor pigments.
Pax-6 was lost from the mammalian genome, and replaced by the rh
gene much later.
The Pax-6 gene mutated to become the rh gene among early mammals.
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Chapter 47 Pre-Test Question 3
Description: (a) The first stage of embryonic development is _____. This process produces _____.
Part A
The first stage of embryonic development is _____. This process produces _____.
Hint A.1
Think about how the zygote becomes a multicellular embryo.
ANSWER:
ovulation ... a zygote
parturition ... a fetus
gastrulation ... a three-layered embryo
neurulation ... a neurula
cleavage ... a cluster of cells
Gastrulation and organogenesis are developmental stages that follow cleavage.
Chapter 47 Pre-Test Question 5
Description: (a) The mesoderm gives rise to _____.
Part A
The mesoderm gives rise to _____.
Hint A.1
Consider the location of mesoderm. Hint: "meso-" refers to middle.
ANSWER:
the gastrointestinal tract and pancreas
the central nervous system
jaws and teeth
the lining of the lungs
skeletal and muscular systems
The muscles and skeleton are of mesodermal origin.
Chapter 47 Question 34
Description: [[Bloom's Taxonomy: Knowledge/Comprehension ]] (a) Cells move to new positions as
an embryo establishes its three germ tissue layers during...
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Part A
Cells move to new positions as an embryo establishes its three germ tissue layers during
ANSWER:
gastrulation.
fertilization.
cleavage.
determination.
induction.
Chapter 47 Question 56
Description: [[Bloom's Taxonomy: Knowledge/Comprehension ]] (a) Changes in the shape of a cell
usually involve a reorganization of the...
Part A
Changes in the shape of a cell usually involve a reorganization of the
ANSWER:
nucleus.
extracellular matrix.
transport proteins.
cytoskeleton.
nucleolus.
Chapter 47 Question 57
Description: [[Bloom's Taxonomy: Application/Analysis ]] (a) Animal development compares to plant
development in that...
Part A
Animal development compares to plant development in that
ANSWER:
animal cells, but not plant cells, migrate during morphogenesis.
plant cells, but not animal cells, migrate during morphogenesis.
neither plant cells nor animal cells migrate during morphogenesis.
plant cells, but not animal cells, undergo convergent extension.
plant cells and animal cells migrate extensively during morphogenesis.
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Chapter 47 Question 59
Description: [[Bloom's Taxonomy: Application/Analysis ]] (a) Select the choice that correctly
associates the organ with its embryonic sources.
Part A
Select the choice that correctly associates the organ with its embryonic sources.
ANSWER:
adrenal gland–ectoderm and mesoderm
anterior pituitary gland–mesoderm and endoderm
thyroid gland–mesoderm and ectoderm
skin–endoderm and mesoderm
brain–mesoderm and endoderm
Chapter 47 Pre-Test Question 10
Description: (a) An embryonic cell that is "totipotent" is one that can _____.
Part A
An embryonic cell that is "totipotent" is one that can _____.
Hint A.1
"Toti" refers to "total."
ANSWER:
by itself, give rise to the entire embryo, as cleavage proceeds
redistribute yolk from the vegetal to the animal pole of the frog embryo
migrate into the center of the blastula during gastrulation
organize the blastula
move mesoderm cells in the blastocoel
In Sperman's work on frog embryos, he showed that the first two blastomeres can develop into
all of the cells of the frog embryo.
Chapter 47 Question 7
Description: [[Bloom's Taxonomy: Application/Analysis ]] (a) Cells transplanted from the neural tube
of a frog embryo to the ventral part of another embryo develop into nervous system tissues. This
result indicates that the transplanted cells were...
Part A
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Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo
develop into nervous system tissues. This result indicates that the transplanted cells were
ANSWER:
mesenchymal.
apoptotic.
differentiated.
totipotent.
determined.
Chapter 11 Pre-Test Question 9
Description: (a) Why can a signaling molecule cause different responses in different cells?
Part A
Why can a signaling molecule cause different responses in different cells?
Hint A.1
Consider how one type of cell may differ from another type of cell.
ANSWER:
Different cells have membrane receptors that bind to different sides of
the signaling molecule.
Different cells possess different enzymes, which modify the signaling
molecule into different molecules after it has arrived.
The transduction pathway in cells has a variable length.
The transduction process is unique to each cell type; to respond to a
signal, different cells require only a similar membrane receptor.
All of the above are correct.
The signal simply initiates a process by activating a membrane receptor. How transduction
proceeds can be quite different for different cells.
Chapter 18 Pre-Test Question 8
Description: (a) How do cells become differentiated?
Part A
How do cells become differentiated?
Hint A.1
How is it possible for a single zygote to give rise to all the cell types in a multicellular organism?
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ANSWER:
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Some cells contain maternal chromosomes and some contain paternal
chromosomes.
The DNA in each cell changes so that the appropriate proteins are
produced.
Paternal effect genes begin the process of differentiation by providing
positional information.
They differentiate through the process of mitosis.
Different genes are expressed so that different proteins are produced.
Cell differentiation results from changes in gene expression.
Chapter 18 Question 2
Description: [[Bloom's Taxonomy: Knowledge/Comprehension ]] (a) Muscle cells differ from nerve
cells mainly because they...
Part A
Muscle cells differ from nerve cells mainly because they
ANSWER:
have different chromosomes.
contain different genes.
have unique ribosomes.
use different genetic codes.
express different genes.
Chapter 18 Question 8
Description: [[Bloom's Taxonomy: Application/Analysis ]] (a) Which of the following statements
about the DNA in one of your brain cells is true?
Part A
Which of the following statements about the DNA in one of your brain cells is true?
ANSWER:
The majority of genes are likely to be transcribed.
It is the same as the DNA in one of your heart cells.
Many genes are grouped into operon-like clusters.
Each gene lies immediately adjacent to an enhancer.
Most of the DNA codes for protein.
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Chapter 18 Misconception Question 4
Part A
How are genes coordinately controlled in eukaryotic cells?
Select all that apply.
ANSWER:
Coordinately controlled genes in eukaryotic cells are located together
on the same chromosome.
Coordinately controlled genes in eukaryotic cells are activated by the
same chemical signals.
Coordinately controlled genes in eukaryotic cells share a set of control
elements.
In eukaryotes, specific transcription factors bind to control elements, promoting transcription of
coordinately controlled genes, even if the genes are on separate chromosomes. Read about
coordinately controlled genes in eukaryotes in Concept 18.2.
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